Retroreflective Coating for Color Without Brightness Loss
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Solution Overview
Problem
Existing retroreflective articles face challenges in maintaining retroreflectivity while incorporating color, as environmental factors such as UV degradation and abrasion affect the colorant, leading to reduced brightness and durability.
Innovation Solution
A conformal wavelength-selective radiation absorbing coating layer is applied adjacent to the structured surface of the retroreflective article using a layer-by-layer self-assembly method, protecting the colorant and allowing for both retroreflective color and significant brightness without significant loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If colorant is incorporated into retroreflective articles, then retroreflective color is achieved, but environmental factors such as UV degradation and abrasion reduce brightness and durability
Solution Approach 1:
A conformal coating layer is applied over the colorant to serve as a protective intermediary. This coating layer shields the colorant from environmental factors including UV radiation and mechanical abrasion, while maintaining the retroreflective optical properties. The coating acts as a mediator between the colorant and the harsh external environment, preserving both color and brightness over time.
Solution Approach 2:
A thin conformal coating layer is deposited over the colorant to protect it from degradation. This flexible thin film provides environmental protection while maintaining the optical performance of the retroreflective article. The conformal nature of the coating ensures complete coverage of the colorant surface.
2Reliability
If conformal coating layer is applied to protect colorant, then durability is improved, but retroreflective brightness may be reduced
Solution Approach 1:
The thickness and optical properties of the conformal coating layer are carefully controlled to optimize the balance between protection and brightness. By adjusting coating parameters such as thickness, composition, and refractive index, the coating provides maximum protection while minimizing impact on retroreflective brightness.
Solution Approach 2:
A thin conformal coating layer is used rather than a thick coating, ensuring that the protective layer does not significantly interfere with light transmission and retroreflective brightness. The thin film provides sufficient environmental protection while maintaining optical performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coating layer effectively protects the colorant from environmental and mechanical challenges, maintaining retroreflective brightness and durability by using a conformal coating that allows for both retroreflective color and significant brightness.
Implementation Method 1
a conformal wavelength-selective radiation absorbing coating layer adjacent to the structured surface... the conformal wavelength-selective radiation absorbing coating layer absorbs radiation of at least one selected wavelength
Implementation Method 2
The air gap behind cube corner elements allows light incident on the cube corner element and encounter active portions of the faces of the cube corner element to be retroreflected. This dielectric face reflectivity is referred to as total internal reflection (TIR).
Data Source
AI summary
The present disclosure provides a retroreflective article. The retroreflective article includes a retroreflective layer including a number of cube corner elements that collectively form a structured surface that is opposite a major surface, and a conformal wavelength-selective radiation absorbing coating layer adjacent to the structured surface. The present disclosure also provides a method of making a retroreflective article. The method includes obtaining a retroreflective layer, and forming a conformal wavelength-selective radiation absorbing coating layer on the retroreflective layer by applying a first material having a first binding group to the structured surface, and applying a second material having a second binding group to the first material. The conformal wavelength-selective radiation absorbing coating layer absorbs radiation of at least one selected wavelength and can impart color (or absorption of at least one wavelength outside of the colored wavelength range) to retroreflective light of the retroreflective article.